1. Technical Field
The present application relates to a solar tracker and a sun tracking method, and more particularly relates to a solar tracker and sun tracking method which may be used in a solar power generator which generates electric power by making a solar panel concentrate incoming sunlight while tracking the sun. The present application further relates to a solar power generator including such a solar tracker and a controller and control program for use in such a solar tracker.
2. Description of the Related Art
A sun-tracking solar power generator is known as a kind of solar power generator, and includes a solar tracker which orients a single or multiple concentrating photovoltaic generator modules that generate electric power by receiving the sunlight toward the sun.
A typical concentrating photovoltaic generator module includes a condenser lens which concentrates incoming sunlight and a solar panel (photovoltaic cell) which generates electric power by receiving the concentrated sunlight. If the solar collector plane of the photovoltaic generator module shifted to stop intersecting with the axis of the incoming sunlight at right angles, then the spot of convergence of the sunlight would not be formed on the surface of the solar panel. In that case, the power generating efficiency might decrease. For that reason, the solar tracker should track the sun accurately so that the solar collector plane of the photovoltaic generator module faces directly the sun.
Japanese Laid-Open Patent Publication No. 2001-217445 teaches calculating the sun's azimuth based on the date and time. The device disclosed in Japanese Laid-Open Patent Publication No. 2001-217445 corrects the azimuth angle and tilt angle by rectifying the error of its internal clock. Specifically, the solar tracker calculates the difference between the meridian passage time according to its internal clock and the point in time when the azimuth angle of the photovoltaic generator module is actually due south. And based on this time difference, the solar tracker rectifies its internal clock so that the photovoltaic generator module exactly faces the sun.